Drifting valve



oct. 7, 19z4 1,510,731I

' H. P. LETART DRIFVTING VALVE 'Filed Nov. v, l'ls ja sneqw-shw. 2

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Patented Get. 7, 1924.

unirse sra/ras HENRY P'. LETART, O'F WATERBURY, CONNECTICUT.

mais? narrative VALVE.

Application led, November To all' 'whom t may concern.' l

Be it known that I, HENRY P. LETART, a citizen of the United States, residing at Waterbury, in the county of New Haven and State' of Connecticut, have invented certain new 'and useful Improvements in Drifting Valves, of which the following is a specification.

The present invention relates to improvements in drifting valves designed to supply to the valve chest and locomotive cylinders during driftingy or running with closed throttle a su'flicient quantity of steam, laden with lubricant whereby to overcome or eliminate the'vacuum produced by operation of the pistons, the cooling of the 'cylinders -by the suction of cool air thereinto and the carbonization of the cylinders which is resultant fromthe foregoing action.

To this end this new invention consists of the construction,` combination and arrangement of parts to be hereinafter specifically described and claimed. Reference will now be had tothe drawings forming a part of this specification, wherein: y

[Figure 1 is a fragmentary view in elevation of a locomotive having my drifting valve applied thereto.

Figure 2 is a vertical sectional view through myV drifting valve, and through a locomotive cylinder and valve chest to which it is connected.

' Figure 8 is a side elevation of the valve.

Figure i is a top plan view thereof. Figure 5 is a horizontal sectional View taken on the line 5-5 of Figure 2, and

Figure 6 is a sectional view of the air inlet and strainer for the valve.

Throughoutthe following detail descripltion and on the several figures of the drawings, similar parts are referred to by like reference characters.

' It should be understood that I may einploy a drifting valve of my type for'each cylinder of the locomotive, but inthe illus-- tration herein set forth I have preferred to disclose a single drifting valve arrangement serving the two cylinders and in such an arrangement the drifting valve is preferably disposed just in advance of the locomotive saddle 1 as shown in Figure 1. Referring to Figure 3, more particularly, the valve will be observed to comprise a casing or housing 2 having a removable cover plate 3 with a central opening therethrough designated 11. This opening is to atmosphere so as to ad- 7, 1919. serial No. 336,485.'

mit atmosphericy pressure into the valve casi ing and the opening is preferab-ly Vprovided with an inletor'strainer tube, shown most clearly in Figure 6 lof the drawing, havingl a threaded connection 5 and screened openings 6v at opposite ends. vThe casing 2 is i specifically set forth. Opposite the connec tion of the pipe 7 to the casing l2the latter is provided with a by-pass 8 communicating with the interior of the casingthrough'the opening 9 at the side and throughthe opening 10 at the bottom, this by-pass leading by way of the conduit 11 to the vmain steam or admission pipes 12 for the steam or valve chests 13. `Within 'the' casing2 is mounted the valve member lproperwhich in this instance Vis provided with three separate spaced piston heads 14, 15, and 16, respectively, all of the same size `land suitably mounted upon a common stem 17 in any desired mechanical manner. These piston heads are preferably provided with piston rings to prevent leakage of pressure .y as customary,but these details need not be more specifically referred to. Beneath the valve member is arranged an expansion spring 18 which possesses just suiiicient-strength or tension to normally sustain the weight of the valve member without compression so.I

spring 18 is compressed vby movement ofthe valve member into the yfull lined'posi-v tion of Figure 3, said valve is in opened position, in which position the auxiliary steam supply will pass through the casing between the heads 15 and 16, the pressure of the said auxiliary supply being equally againstv the top side of the head 16 and the underside of the head 15. l f

The side of the casing 2 at a point intermediate the heads 14 and 15 of the valve member is provided with an outlet 19 to permit the escape of any leakage of any pressure which happens to pass the head l5 by virtue of worn rings.

'lhe valve chest construction is ot the conventional torni employing a hollow piston valve designated 2G and this portion oi the locomotive construction does not require speciic description.

In the use or" this invention it will be uii derstood that the valve under normal conditions is in its closed position with the val-ve member at its uppermost position. lllhen the throttle'ol' the locomotive is opened and steam supplied'to the admission part ot' the valve chests'through the pipes lthe pressure is also presentin the conduits ll and will enterthe bottom ot the casing 2 through the port l0 into the spring chamber l0 where it will coact to maintain the valve member in closed position. lllhile the engine is running, however, and when the throttle is closed, the reciprocation ot the cylinder pistons, as is well known, produces a vacuum condition which acting through the valve chests vtends to produce a vacuum in the spring chamber l0 and necessarily in the conduits ll. The atmospheric pressure entering through the upper end of the casing at l becomes effective upon the head lll which being greater than the tension ol: the spring 'i8 moves the valve member down against its seat indicated at 2l. The valve is now in open position 'so that the steam from the Iboiler will pass by the pipe 7 through the valve and bypass 8 to the valve chests where the steam will maintain the temperature in the cylinders at a high point and will relieve the vacuum condition as well as supply the necessary lubrication. Upon opening or' the throttle v alve and the introduction of pressure into the admission part of the valve chest, this pressure being greater by far than the atmospheric pres-- sure upon the open end of the valve member will become effective against the lower valve head 16 and in conjunction with the spring 18 will cause the valve member to resume its normal closed position. lt will therefore be apparent that so 'long as pressure ispresent inthe admission part of the valve chest the drifting valve is closed 'whereas the vacuum condition in the'valve chest during movement ot the locomotive due to the action of the cylinder piston when the throttle is closed, in other words when the locomotive is drifting, causes the valve y to open and admit a limited quantity ot live steam for lubricating` the parts.

Having thus described my invention, what vl claiinas new is:

l. A drifting valve tor locomotives, including a valve casing open at one end to the atmosphere, a valve member slidable within the casing and lie-ving a piston head at each end thereof, a conduit leading from the lower end of the casing to the normal steam supply ot the locomotive lwhereby the pres sure thereof acts upon the lower lhead to hold the valve in a closed position while the suction ot the engine cylinder cooperates with the atmospheric pressure on the upper piston head to move the valve into open position when the locomotive is running with the throttle closed, and means controlled by the movements of the valve member for supplying auxiliary steam to the steam chest when the valve is in an open position.

2. Vllhe combination rwith the steam chest, its steam supply pipe, and the boiler ot a locomotive, ot' a drifting yvalve comprising a casing, a piston valve therein having a series ot spaced heads, one end of said casing being open tothe atmosphere to subject the outer tace ot one o said valve eads )to atmospheric pressure, a ,conduit leading trom the boiler and entering the casing at one side thereof, a. branch conduit leading ifrointlie steam supply pipe ot' the steam chest to the casing to admit pressure Ytrom the chest beneath a face of a second valve head when the engine ris running with the throttle open tending to hold said second head in position norinally closing the boiler conduit entrance and to relieve pressure from said face when the engine is ruiming with the throttle closed, and a by-pass leading 'from the side ot the casing to said branch-conduit, said by-pass and branch conduit `serving to convey auxiliary steam to the steam chest when the locomotive is ruiming with the throttle closed and the piston valve has'been moved by atmospheric.pressure .acting upon the outer tace of the irstnientioned piston head to cause the second mentioned piston head to uncover theentrance fromthe casing to the boiler conduit.

The combination with thesteam chest, its steam supply pipe rand the boiler of a locomotive, of a drifting valve comprising a casing having an opening inthe upper end thereof, alpiston valve therein provided with a series ot pistonheads the .uppermost one ot which Ais subject to .atmospheric pressure through said opening, a conduit leading irom the boiler tothe side .of the casing, a branch conduit leading trom the lower end of the casing tothe steamsupply pipe, a by-pass leading troni Vtheside of the casii'ig to the steam supply pipe through which auxiliary steam conveyed to the 'through the boiler conduit is adapted to pass to the ste-am chest, .asecond valve head in the lower end of said casing, and a spring between thecsecond valve head and the .lower end ot .the casing acting upon said valve head in vconjunction with the steam chest pressure insaid branch. conduit to cause said second valvehead to occupy a position closing the boiler conduit and bypass, saidsecond valve-head being automatically shifted by the atmospheric pressure upon said first mentioned valve head to a position opening the boiler conduit and by-pass upo-n the reduction of pressure in the steam chest when the engine is running with the throttle closed.

4. A drift valve for locomotives, including an upright valve casing having the upper end thereof open to the atmosphere, a valve member slidable up and down within the casing and having a piston head at each end thereof, a spring normally supporting the valve member in a closed position, a conduit leading from the lower end of the easing to a steam supply pipe of the locomotive, whereby the normal steam pressure Vacts upon the lower piston head and cooperates with the spring to hold the valve in a Closed position while the suction of the cylinder cooperates with the atmospheric pressure on the upper piston head to move the valve downwardly against the action of the spring when the locomotive is running with the throttle closed, andmeans controlled by the movements of the valve member for supplying auxiliary steam to the steam chest when the valve is in a lowered position.

In testimony whereof I afIiX my signature.

HENRY l?. LETART. 

